Replacing the new group file with the old one worked well (booting from a CD). The system now works. sudo, mysql, apache, samba all are working again. The MediaWiki problem is still there, so I'll log a different bug for that.
I would really like to know why this happened, and why extra groups were added to the group file, such as: kvm libvirtd sambashare ssl-cert winbind_priv netdev messagebus -- gid changed after intrepid to jaunty upgrade https://bugs.launchpad.net/bugs/367204 You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
